staging: iio: cdc: ad7746: use dt for capacitive channel setup.

Ditch platform_data fields in favor of device tree properties for
configuring EXCA and EXCB output pins and setting the capacitive channel
excitation level.

As this covers all current use cases for the platform_data struct, remove
ad7746.h header file since it's no longer needed.
Signed-off-by: Lucas Stankus <lucas.p.stankus@gmail.com>
Link: https://lore.kernel.org/r/3e7f2a0a8960cece185f518ff2b7ceb87891edcd.1619841953.git.lucas.p.stankus@gmail.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/staging/iio/cdc/ad7746.c

@@ -18,8 +18,6 @@
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
 
-#include "ad7746.h"
-
 /*
  * AD7746 Register Definition
  */
@@ -676,10 +674,11 @@ static const struct iio_info ad7746_info = {
 static int ad7746_probe(struct i2c_client *client,
 			const struct i2c_device_id *id)
 {
-	struct ad7746_platform_data *pdata = client->dev.platform_data;
+	struct device *dev = &client->dev;
 	struct ad7746_chip_info *chip;
 	struct iio_dev *indio_dev;
 	unsigned char regval = 0;
+	unsigned int vdd_permille;
 	int ret;
 
 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*chip));
@@ -703,26 +702,39 @@ static int ad7746_probe(struct i2c_client *client,
 	indio_dev->num_channels = ARRAY_SIZE(ad7746_channels);
 	indio_dev->modes = INDIO_DIRECT_MODE;
 
-	if (pdata) {
-		if (pdata->exca_en) {
-			if (pdata->exca_inv_en)
-				regval |= AD7746_EXCSETUP_NEXCA;
-			else
-				regval |= AD7746_EXCSETUP_EXCA;
-		}
+	if (device_property_read_bool(dev, "adi,exca-output-en")) {
+		if (device_property_read_bool(dev, "adi,exca-output-invert"))
+			regval |= AD7746_EXCSETUP_NEXCA;
+		else
+			regval |= AD7746_EXCSETUP_EXCA;
+	}
 
-		if (pdata->excb_en) {
-			if (pdata->excb_inv_en)
-				regval |= AD7746_EXCSETUP_NEXCB;
-			else
-				regval |= AD7746_EXCSETUP_EXCB;
-		}
+	if (device_property_read_bool(dev, "adi,excb-output-en")) {
+		if (device_property_read_bool(dev, "adi,excb-output-invert"))
+			regval |= AD7746_EXCSETUP_NEXCB;
+		else
+			regval |= AD7746_EXCSETUP_EXCB;
+	}
 
-		regval |= AD7746_EXCSETUP_EXCLVL(pdata->exclvl);
-	} else {
-		dev_warn(&client->dev, "No platform data? using default\n");
-		regval = AD7746_EXCSETUP_EXCA | AD7746_EXCSETUP_EXCB |
-			AD7746_EXCSETUP_EXCLVL(3);
+	ret = device_property_read_u32(dev, "adi,excitation-vdd-permille",
+				       &vdd_permille);
+	if (!ret) {
+		switch (vdd_permille) {
+		case 125:
+			regval |= AD7746_EXCSETUP_EXCLVL(0);
+			break;
+		case 250:
+			regval |= AD7746_EXCSETUP_EXCLVL(1);
+			break;
+		case 375:
+			regval |= AD7746_EXCSETUP_EXCLVL(2);
+			break;
+		case 500:
+			regval |= AD7746_EXCSETUP_EXCLVL(3);
+			break;
+		default:
+			break;
+		}
 	}
 
 	ret = i2c_smbus_write_byte_data(chip->client,

drivers/staging/iio/cdc/ad7746.h

-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * AD7746 capacitive sensor driver supporting AD7745, AD7746 and AD7747
- *
- * Copyright 2011 Analog Devices Inc.
- */
-
-#ifndef IIO_CDC_AD7746_H_
-#define IIO_CDC_AD7746_H_
-
-/*
- * TODO: struct ad7746_platform_data needs to go into include/linux/iio
- */
-
-#define AD7466_EXCLVL_0		0 /* +-VDD/8 */
-#define AD7466_EXCLVL_1		1 /* +-VDD/4 */
-#define AD7466_EXCLVL_2		2 /* +-VDD * 3/8 */
-#define AD7466_EXCLVL_3		3 /* +-VDD/2 */
-
-struct ad7746_platform_data {
-	unsigned char exclvl;	/*Excitation Voltage Level */
-	bool exca_en;		/* enables EXCA pin as the excitation output */
-	bool exca_inv_en;	/* enables /EXCA pin as the excitation output */
-	bool excb_en;		/* enables EXCB pin as the excitation output */
-	bool excb_inv_en;	/* enables /EXCB pin as the excitation output */
-};
-
-#endif /* IIO_CDC_AD7746_H_ */